ミヤヤマ　タカミツ   Takamitsu Miyayama   宮山　貴光    所属   医学部 医学科    職種   助教
論文種別	原著
言語種別	英語
査読の有無	査読あり
表題	Roles of COMM-domain-containing 1 in stability and recruitment of the copper-transporting ATPase in a mouse hepatoma cell line
掲載誌名	正式名：Biochemical Journal 略　 称：Biochem J ISSNコード：14708728/02646021
巻・号・頁	429(1),pp.53-61
著者・共著者	MIYAYAMA Takamitsu†, HIRAOKA Daisuke†, KAWAJI Fumika, NAKAMURA Emi, SUZUKI Noriyuki, OGRA Yasumitsu*
担当区分	筆頭著者
発行年月	2010/07
概要	A novel function of COMMD1 {COMM [copper metabolism MURR1 (mouse U2af1-rs1 region 1)]-domain-containing 1}, a protein relevant to canine copper toxicosis, was examined in the mouse hepatoma cell line Hepa 1-6 with multi-disciplinary techniques consisting of molecular and cellular biological techniques, speciation and elemental imaging. To clarify the function of COMMD1, COMMD1-knockdown was accomplished by introducing siRNA (small interfering RNA) into the cells. Although COMMD1-knockdown did not affect copper incorporation, it inhibited copper excretion, resulting in copper accumulation, which predominantly existed in the form bound to MT (metallothionein). It is known that the liver copper transporter Atp7b (ATP-dependent copper transporter 7beta), localizes on the trans-Golgi network membrane under basal copper conditions and translocates to cytoplasmic vesicles to excrete copper when its concentration exceeds a certain threshold, with the vesicles dispersing in the periphery of the cell. COMMD1-knockdown reduced the expression of Atp7b, and abolished the relocation of Atp7b back from the periphery to the trans-Golgi network membrane when the copper concentration was reduced by treatment with a Cu(I) chelator. The same phenomena were observed during COMMD1-knockdown when another Atp7b substrate, cis-diamminedichloroplatinum, and its sequestrator, glutathione ethylester, were applied. These results suggest that COMMD1 maintains the amount of Atp7b and facilitates recruitment of Atp7b from cytoplasmic vesicles to the trans-Golgi network membrane, i.e. COMMD1 is required to shuttle Atp7b when the intracellular copper level returns below the threshold.
DOI	10.1042/BJ20100223BJ20100223 [pii]
文献番号	20433422